Yokogawa YS150-012/A31 S3 Multifunction Controller

Overview

The Yokogawa YS150‑012/A31 S3 is a high-precision single-loop multifunction process controller from Yokogawa’s YS series. Designed for reliable operation in industrial settings, it efficiently regulates temperature, pressure, flow, or other process variables. Despite the YS150 series being discontinued since 2008, this model remains widely used in legacy systems and is available for spare or replacement purposes.

The /A31 variant provides RS‑485 communication, enabling Modbus, PC-Link, and peer-to-peer protocol integration for seamless connectivity with host systems and engineering tools.

Technical Specifications

General

• Model: YS150‑012/A31 S3
• Series: YS150 Single-Loop Controller
• Origin: Japan
• Weight: 1.5 kg

Control & I/O

• Control Loop: Single-loop PID
• Control Functions: Standard PID with auto-tuning; supports optional advanced modes (cascade, feedforward where applicable)
• Analog Input: 1 channel, compatible with 4–20 mA, 1–5 V, thermocouple, RTD
• Analog Output: 1 channel, configurable for 4–20 mA or 1–5 V
• Digital I/O: Typically 4 digital inputs and 2 relay outputs for remote operation, alarms, and status signaling
• Communication Interface: RS‑485 (/A31 option), supporting Modbus, PC-Link, and peer-to-peer communication

Performance

• Control Cycle / Sampling Time: 100 ms
• Accuracy & Stability: Industrial-grade regulation for precise control of process variables

Display & User Interface

• Front Panel: Integrated LED display (5-digit or equivalent) with tactile keys for local monitoring and configuration

Electrical & Power

• Power Supply: 100–240 V AC, 50/60 Hz (model-dependent)
• Power Consumption: 20 VA

Environmental

• Operating Temperature: 0 °C to +50 °C
• Storage Temperature: −20 °C to +60 °C
• Humidity: 5 % to 95 % RH, non-condensing

Physical & Mounting

• Dimensions: 144 mm × 144 mm × 150 mm
• Protection Rating: IP54
• Mounting: Standard panel cut-out with bezel interface

Applications

The YS150‑012/A31 S3 is suitable for process control in industries such as:

• Petrochemical and chemical plants
• Food & beverage production
• Power generation systems
• Environmental monitoring and water treatment
• Any industrial system requiring precise single-loop process control

FAQ

Q: Is this model still supported by Yokogawa?

A: The YS150 series has been discontinued since 2008. Units are available as spare/legacy components for existing systems.

Q: What communication protocols does /A31 support?

A: RS‑485 communication supports Modbus, PC-Link, and peer-to-peer protocols.

Q: Can this controller be used in cascade control loops?

A: Yes, advanced PID functions like cascade and feedforward are supported where applicable.

Q: What are similar models in the YS series?

A: The YS1500 and YS1000 series are modern replacements with expanded I/O and enhanced communication options.